1. Field of Invention
This invention relates to oil recycling devices. Specifically, the present invention relates to devices for maintaining clean engine oil while an engine is operating.
2. Description of the Related Art
Oil is a lubricant in a variety of applications ranging from electric generators to printing presses to automobiles. Such applications require clean oil with minimal liquid, gas, and solid contaminants.
Typical engine oil contains a variety of solid, gas, and liquid contaminants. Engine oil is contaminated by gases from engine cylinder blow-by; by solids from engine component wear, and by liquids from coolant leeks and condensed blow-by gasses. Liquids combine with sulfur and other compounds from cylinder blow-by, creating corrosive acids, such as sulfuric acid. These contaminants corrode engine parts and deplete special minerals and detergents added to help maintain important oil properties including lubricity and viscosity.
To reduce problems associated with oil contamination, full-flow filters were developed. All oil circulating around an engine equipped with a full flow filter is directed through the filter or filter housing. High flow requirements limit the ability of conventional full flow filters to remove very small solid contaminants. Large particles of twenty microns or larger often pass through such filters and contribute to engine wear. In addition, conventional full flow filters are ineffective at removing liquid contaminants from the oil.
To remove both solid and liquid contaminants from engine oil, mobile, i.e., onboard oil refining systems were developed. The systems continually remove, clean, and replace small amounts of oil from the engine as the engine operates. The systems include a special evaporation compartment that attaches to a by-pass filter. The evaporation compartment removes both gas and liquid contaminants from the oil, and the filter removes solid contaminants as small as one micron in diameter. Such small particles are often smaller than engine tolerances and do not contribute to engine wear. These oil refining systems may obviate the need for interval oil changes but require interval filter changes.
The systems require a large evaporation compartment and an expensive electric heating element. The heating element increases the risk of the systems exploding due to gas ignition. To reduce explosion danger, the evaporation compartments are constructed of strong, thick, and heavy metal. Also, the heating element eliminates a beneficial oil cooling effect that would otherwise occur.
The large size of the systems limits installation to large trucks and automobiles with ample space. Installation on most modern automobiles is difficult and expensive due to limited space. In addition, electrical connections required for the electric heating elements complicate installation, and decrease the reliability of the systems. Public acceptance of the systems has been minimal as a result of these problems.
Hence, a need exists in the art for a safe, space-efficient and cost-effective mobile oil recycling system that removes both solid and liquid contaminants from oil. There is a further need for a system that may be easily installed on modern automobiles.
The need in the art is addressed by mobile oil recycling system of the present invention. In the illustrative embodiment, the inventive system is adapted for use with a combustion engine and includes an evaporation chamber for changing the pressure of the engine oil from a first pressure to a second pressure lower than the first pressure. Metering holes in a textured three-dimensional evaporation surface at the second pressure allow oil to spread over the three-dimensional surface area and evaporate contaminants from the oil. This evaporation process has a desirable oil cooling effect.
In a specific embodiment, the system includes a filtering system for removing solid contaminants from the oil. A housing contains and supports the filtering system and the evaporation chamber, and directs the flow of oil through the system. The housing includes a base having an oil inlet for allowing pressurized oil to enter the oil recycling system and an oil outlet for allowing oil at atmospheric pressure to exit the recycling system. An evaporation surface in the liquid and gas contaminant removal chamber facilitates the removal of gas and liquid contaminants from the oil. A vent in the housing allows vaporized contaminants to escape.
The housing includes a first wall and a second wall. The inside surface of the first wall is the evaporation surface and is textured for maximizing evaporation surface area. The filtering system includes a space between the first wall and the second wall. Oil enters the space via the oil inlet in the base of the housing. The filtering system includes a jet on the oil inlet for creating a centrifugal flow in the space that forces large particles out of circulation.
In the illustrative embodiment, the housing includes a spin-on filter canister. The filtering system includes a gradient density low-micron filter that removes solid contaminants and helps absorb and neutralize liquid contaminants. The filter is located between the space and the first wall. Strategically located holes in the first wall allow oil to pass through the filter and onto the evaporation surface. The first wall and the second wall are concentric tubular walls, capped at one end by the base of the housing, and at the other end by an end cap.
The novel design of the present invention is facilitated by grooves or channels in the evaporation surface that increase the rate of evaporation of contaminants from oil on the surface, thereby obviating the need for an electric heater element. This texturing of the surface to create a three-dimensional surface eliminates wasted space and excess weight inherent in systems that have evaporation units and heater elements stacked on filters.